This invention relates to an apparatus for illuminating paintings, posters, and those duplications (hereinafter collectively referred to as "paintings") and a frame to which such an illumination apparatus is attached.
A particular paint that emits or reflects certain light upon reception of ultraviolet radiation from an ultraviolet lamp (so called "black light") has been devised and used for production of paintings. The paintings are produced in a fashion that such a particular paint is placed in some part of the painting area, e.g., in a crescent portion over a circle area that is painted by a regular paint as the sun. When one of such paintings is observed under a sufficiently bright incandescent lamp, the sun portion is literally perceived as the sun while remaining portions depicting a landscape are seen brightly. That is, in this situation, this painting is observed as a daytime landscape. To the contrary, when the incandescent lamp is dimmed and the painting is observed with an ultraviolet light radiated from an ultraviolet lamp (black light), the sun portion is perceived as a dark portion, and only the crescent portion emits light. That is, in this situation, this painting is observed as a nighttime landscape.
We have developed some illumination apparatus in which the ultraviolet lamp is normally turned on and the incandescent lamp can be turned on and off by a switch control, to illuminate paintings using those paints. With such an illumination apparatus, the incandescent lamp is turned on and off upon control of the switch, thereby arbitrarily changing, between the daytime landscape and the nighttime landscape, the appearance of the paintings using the particular paint.
Switching control of the incandescent lamp, which is performed each time, however, creates inconvenience and abrupt changes from daytime to nighttime and thus makes such changes unnatural. To eliminate such inconvenience and to make changes between the daytime and nighttime landscapes closely natural as much as possible, we have devised an illumination apparatus that automatically repeats by a control circuit a sequence that the incandescent lamp is turned on when a previously set time elapses, gradually increases the lamp brightness, maintains the brightness for a prescribed period, is gradually dimmed, and then is turned off. In this illumination apparatus, it is to be noted that the ultraviolet lamp is normally turned on. According to the illumination apparatus, no switching control of the incandescent performed each time is required, and furthermore, the painting is perceived, as a nighttime landscape due to the ultraviolet radiation from the ultraviolet lamp where the incandescent lamp is turned off, then gradually as a morning landscape as shifted from the nighttime landscape in accordance with increase of brightness upon turning on of the incandescent lamp, then as a daytime landscape where the incandescent lamp is brightest, then gradually as a sunset landscape as the incandescent lamp is more dimmed, and as the nighttime landscape again when the incandescent lamp is turned off.
However, because the illumination apparatus thus described has the ultraviolet lamp normally turned on even while the incandescent lamp is turned on, the particular paint may emit light upon the ultraviolet radiation from the ultraviolet lamp, thereby rendering the painted portions of the particular paint recognizable by observers of the paintings, in association with watching angles of the observers, brightness of the incandescent lamp at the peak, number of the incandescent lamps, and size of the paintings, even where the incandescent lamp is turned on and brightness of the lamp reaches the peak or maximum. This makes difficult to adequately express differences between the daytime landscape and nighttime landscape and negates unexpectedness at a time of changes from the daytime landscape to the nighttime landscape, thereby reducing the commercial value of the apparatus.